In Class 10 Science Ch 6-Life Processes NCERT Solution, we delve into the essential life processes that are vital for the survival of living organisms. This chapter explains the key physiological processes such as nutrition, respiration, transportation, and excretion that occur in plants and animals.
Understanding these processes helps us appreciate how organisms maintain their internal balance and function effectively in their environment. The chapter provides a detailed overview of each process, exploring their mechanisms and significance in sustaining life.
Class 10 Science Ch 6-Life Processes NCERT Solution
🔹 Page 81 – In-Text Questions
1. Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
Answer:
In multicellular organisms, all cells are not in direct contact with the environment. Diffusion is a slow process and cannot meet the oxygen demands of all body cells efficiently. Hence, a proper respiratory system and transport system are needed.
2. What criteria do we use to decide whether something is alive?
Answer:
The criteria to decide whether something is alive includes movement, growth, respiration, reproduction, excretion, and response to stimuli. If an organism shows all life processes, it is considered alive.
3. What are outside raw materials used for by an organism?
Answer:
Outside raw materials like water, carbon dioxide, and minerals are used for energy production and growth. For example, plants use carbon dioxide and water for photosynthesis.
4. What processes would you consider essential for maintaining life?
Answer:
Essential life processes are:
- Nutrition
- Respiration
- Transportation
- Excretion
🔹 Page 87 – In-Text Questions
5. What are the differences between autotrophic and heterotrophic nutrition?
Answer:
| Feature | Autotrophic Nutrition | Heterotrophic Nutrition |
|---|---|---|
| 1. Food preparation | Organism prepares its own food | Depends on others for food |
| 2. Mode | Photosynthesis (using sunlight) | Ingestion and digestion |
| 3. Example | Green plants, algae | Animals, fungi, most bacteria |
6. Where do plants get each of the raw materials required for photosynthesis?
Answer:
- Carbon dioxide: From air through stomata
- Water: From soil via roots
- Sunlight: From the sun
- Chlorophyll: Present in chloroplasts in green leaves
7. What is the role of the acid in our stomach?
Answer:
Hydrochloric acid in the stomach:
- Creates an acidic medium for the action of enzyme pepsin
- Kills bacteria present in food
8. What is the function of digestive enzymes?
Answer:
The function of digestive enzymes is to break down complex food molecules into simpler, absorbable forms. For example, amylase breaks down starch into sugars, pepsin digests proteins into peptides, and lipase breaks down fats into fatty acids and glycerol. These enzymes help in the proper digestion and absorption of nutrients in the body.
9. How is the small intestine designed to absorb digested food?
Answer:
The small intestine is specially adapted for the absorption of digested food. Its inner lining has numerous finger-like projections called villi, which increase the surface area for absorption. Each villus contains a network of blood capillaries and lymph vessels that help in the quick transport of absorbed nutrients into the bloodstream. The walls of the small intestine are also thin and richly supplied with blood, making absorption efficient.
🔹 Page 91 – In-Text Questions
10. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Answer:
Terrestrial organisms breathe in oxygen directly from the air, which contains more oxygen than water. In contrast, aquatic organisms obtain oxygen dissolved in water, which is available in much lower concentration. Therefore, terrestrial organisms get oxygen more easily and efficiently, giving them an advantage in respiration.
11. What are the different ways in which glucose is oxidised to provide energy in various organisms?
Answer:
| Organism Type | Glucose Breakdown Pathway |
|---|---|
| With oxygen (aerobic) | Glucose → Pyruvate → CO₂ + H₂O + energy (in mitochondria) |
| Without oxygen (anaerobic) | Glucose → Pyruvate → Ethanol + CO₂ + less energy (in yeast) |
| In muscles (no oxygen) | Glucose → Pyruvate → Lactic acid + less energy |
12. How is oxygen and carbon dioxide transported in human beings?
Answer:
- Oxygen: Transported by haemoglobin in red blood cells
- Carbon dioxide: Mostly transported in dissolved form in blood plasma
13. How are the lungs designed in human beings to maximise the area for exchange of gases?
Answer:
In human beings, the lungs are designed to maximise the surface area for gas exchange. Inside the lungs, the bronchi divide into smaller tubes called bronchioles, which further end in tiny air sacs called alveoli. Each lung contains millions of alveoli, and their walls are thin and richly supplied with blood capillaries. The large number and balloon-like structure of alveoli greatly increase the surface area, allowing efficient exchange of oxygen and carbon dioxide between the air and blood.
🔹 Page 96 – In-Text Question
14. What are the components of the transport system in human beings? What are the functions of these components?
Answer:
The main components of the transport system in human beings are:
- Heart:
It is a muscular organ that pumps blood throughout the body. It ensures continuous circulation of oxygenated and deoxygenated blood through different chambers and blood vessels. - Blood:
Blood is the fluid that transports oxygen, carbon dioxide, nutrients, hormones, and waste products. It consists of:- Red Blood Cells (RBCs): Carry oxygen.
- White Blood Cells (WBCs): Fight infections.
- Platelets: Help in blood clotting.
- Plasma: Transports nutrients, hormones, and waste.
- Blood Vessels:
These are the channels through which blood flows. They include:- Arteries: Carry oxygenated blood away from the heart.
- Veins: Carry deoxygenated blood back to the heart.
- Capillaries: Allow exchange of materials between blood and body tissues.
15. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Answer:
It ensures efficient oxygen supply to body tissues which is essential for high energy demands, especially in warm-blooded animals like birds and mammals.
16. What are the components of the transport system in highly organised plants?
Answer:
In highly organised plants, the transport system consists of two main conducting tissues:
- Xylem:
- Transports water and minerals from the roots to the rest of the plant.
- It consists of vessels, tracheids, xylem parenchyma, and xylem fibres.
- Phloem:
- Transports food (mainly sugars) prepared in the leaves to all parts of the plant.
- It consists of sieve tubes, companion cells, phloem parenchyma, and phloem fibres.
These tissues form a network of tubes that help in the efficient transport of substances throughout the plant.
17. How are water and minerals transported in plants?
Answer:
Water and minerals are transported in plants through xylem tissue. The process involves the following steps:
- Absorption: Roots absorb water and minerals from the soil through root hairs.
- Upward Movement: The absorbed water moves upward through the xylem vessels present in roots, stem, and leaves.
- Transpiration Pull: The loss of water from leaves through tiny pores called stomata creates a suction force, called transpiration pull, which helps in pulling water upward from the roots to the leaves.
- Cohesion and Adhesion: The properties of water molecules (cohesion between water molecules and adhesion to xylem walls) assist in the continuous upward flow of water.
Thus, water and minerals are efficiently transported from the soil to all parts of the plant.
18. How is food transported in plants?
Answer:
Answer:
Food is transported in plants through a tissue called phloem. This process is known as translocation. It involves the following steps:
- The food (mainly sugars) prepared in the leaves during photosynthesis is loaded into the phloem tissues.
- The movement of food occurs from source (leaves) to sink (storage organs or growing parts).
- This movement is bidirectional (can go up or down the plant).
- The process requires energy in the form of ATP.
- The pressure created by loading food into the phloem causes water to enter by osmosis, which helps in pushing the food through the phloem to various parts of the plant.
Thus, phloem helps in the active and regulated transport of food in plants.
🔹 Page 98 – In-Text Questions
19. Describe the structure and functioning of nephrons.
Answer:
Structure of Nephron:
A nephron is the basic structural and functional unit of the kidney. Each kidney contains about 1 million nephrons. A nephron consists of the following parts:
- Bowman’s capsule – A cup-shaped structure that surrounds a network of capillaries called the glomerulus.
- Glomerulus – A cluster of thin-walled capillaries formed from afferent arterioles.
- Proximal convoluted tubule (PCT) – The coiled portion after Bowman’s capsule.
- Loop of Henle – A long U-shaped tubule that dips into the medulla.
- Distal convoluted tubule (DCT) – The coiled tubule after the loop of Henle.
- Collecting duct – Receives urine from several nephrons and transports it to the renal pelvis.
Functioning of Nephron:
- Filtration:
Blood enters the glomerulus under high pressure. Water, urea, glucose, salts, and other small molecules are filtered into the Bowman’s capsule, while larger molecules (like proteins) and blood cells remain in the blood. - Reabsorption:
Useful substances like glucose, amino acids, water, and salts are reabsorbed from the tubule into the surrounding blood capillaries, mainly in the proximal tubule and loop of Henle. - Secretion:
Additional wastes like excess ions and drugs are secreted into the tubule from the blood. - Urine formation:
The remaining fluid, containing urea and other waste products, is urine. It passes into the collecting duct and is transported to the bladder via the ureters.
20. What are the methods used by plants to get rid of excretory products?
Answer:
Unlike animals, plants do not have a well-developed excretory system. However, they have developed various simple and effective methods to eliminate their waste products. These include:
1. Storage in Cellular Structures:
- Plants often store waste materials such as tannins, resins, latex, and alkaloids in cell vacuoles.
- These substances are either harmless or less toxic and do not interfere with the plant’s metabolic activities.
- Example: Gums and resins accumulate in old xylem tissues.
2. Excretion through Leaves:
- Some waste products are stored in old or aging leaves.
- These leaves are eventually shed off (abscission), and the waste is removed from the plant body.
- This is a passive yet effective way of removing solid or semi-solid waste.
3. Excretion through Bark:
- Certain excretory substances are deposited in the outer layers of the bark, which eventually peel off.
- This helps in removing waste accumulated in the outer tissues over time.
4. Gaseous Waste Removal:
- Plants produce oxygen (during photosynthesis) and carbon dioxide (during respiration) as gaseous wastes.
- These gases are excreted through:
- Stomata in leaves.
- Lenticels in stems and woody parts.
21. How is the amount of urine produced regulated?
Answer:
The amount of urine depends on:
- Water intake
- Amount of dissolved waste
- Hormonal control by ADH (Anti-Diuretic Hormone)
🔹 End Exercises – Page 99
1–4. (MCQs)
- (c) excretion
- (a) transport of water
- (d) all of the above
- (b) mitochondria
5. How are fats digested in our bodies? Where does this process take place?
Answer:
Fats are emulsified by bile from the liver in the small intestine. Then, lipase enzyme breaks them into fatty acids and glycerol for absorption.
6. What is the role of saliva in the digestion of food?
Answer:
Saliva moistens food and contains salivary amylase (ptyalin) which breaks starch into sugar in the mouth.
7. What are the necessary conditions for autotrophic nutrition and what are its by-products?
Answer:
Conditions: Sunlight, chlorophyll, CO₂, water
By-products: Glucose and Oxygen
8. What are the differences between aerobic and anaerobic respiration? Name some organisms that use anaerobic mode.
Answer:
| Feature | Aerobic Respiration | Anaerobic Respiration |
|---|---|---|
| Oxygen required | Yes | No |
| Energy yield | High | Low |
| End products | CO₂ and H₂O | Alcohol/lactic acid + CO₂ |
| Example organisms | Humans, plants | Yeast, some bacteria, muscles |
9. How are the alveoli designed to maximise the exchange of gases?
Answer:
Alveoli have:
- Large surface area
- Thin walls
- Rich blood supply
These features help efficient gas exchange.
10. What would be the consequences of a deficiency of haemoglobin in our bodies?
Answer:
Low haemoglobin leads to anaemia, causing fatigue, weakness, shortness of breath, and reduced oxygen supply to cells.
11. Describe double circulation of blood in human beings. Why is it necessary?
Answer:
Double circulation means blood passes through the heart twice in one complete cycle:
- Pulmonary circulation: Heart → Lungs → Heart
- Systemic circulation: Heart → Body → Heart
It ensures oxygen-rich and oxygen-poor blood don’t mix, which is vital for efficient energy supply.
12. What are the differences between the transport of materials in xylem and phloem?
| Feature | Xylem | Phloem |
|---|---|---|
| Material | Water and minerals | Food (sugars, amino acids) |
| Direction | One-way (roots to leaves) | Both directions |
| Energy | Passive (no energy used) | Active (requires energy) |
13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.
| Feature | Alveoli | Nephrons |
|---|---|---|
| Structure | Tiny air sacs with thin walls | Tubular structure with Bowman’s capsule |
| Function | Exchange of oxygen and CO₂ | Filtration of blood and urine formation |
| Location | Lungs | Kidneys |
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Understanding life processes is essential to comprehend how living organisms function and sustain life. In this chapter, we explored key biological processes such as nutrition, respiration, transportation, and excretion in both plants and animals. These functions are crucial for maintaining life and achieving coordination among various organs and systems in the body.
Thus, we conclude that all living organisms perform certain basic functions to maintain their life, which are collectively known as life processes.
This chapter helps build a strong foundation in biology and prepares students to appreciate the complex yet fascinating mechanisms that support life on Earth.